Use: Often used as a means of qualification/non-commitment, to express a sense of uncertainty or lack of balance.

Metaphor: Imbalance is Bad. Imbalance is Uncertainty.

Explanation: In relation to the first example, the hand teeters because it is signifying a value judgement. It is not signifying "bad" but a more qualifying "not great" or "so-so" as the imbalance in the gesture is usually slight and usually not very exaggerated or rapid. Imbalance also signifies an uncertain positioning in the physical world, something that is not stable.

Origin: No one likes to fall down. Some of our earliest negative experiences as toddlers/children is falling down, possibly because we've lost balance. These falls can have a range of results from small scrapes on the knee to broken bones. The idea of imbalance then has an early negative connotation, one that is easily applied to abstract thinking. This carries over into our adult life as well. If we are walking across a path of stones placed across a river, we are wary of stones that lack balance. We step on them cautiously. They are not to be trusted. People who exhibit behaviors that may be untrustworthy, can also be described as "unbalanced". Relying upon them, like stepping on a stone without being cautious, could prove disasterous.

Sound: There is a sound associated with this hand gesture that is usually a high pitched "Meh" that extends for awhile.

Facial features: Face scrunches up on one side, also adding to the idea of "imbalance" as the face itself is no longer "balanced".